lib: reworked the bookmark parser

lib: reworked the bookmark parser

Some of the buffer limit checking seemed to be missing, so this
reworks the code so it does the following more consistently:

	- advance begin pointer
	- check limit
	- abort if over
	- use data

Also, in analyzing the records on my 9550, 8700, and 7750, I noticed
a new Index field, and some potential IDs that I haven't linked to
anything else yet.

Section 0x11 looks like this:
Section 0x11:
	Starts with 0x85 or 0x87
		- 4 byte record ID?
		- 1 byte record index (00, 01, 02, 03, 04)
	Code: 0x04
		- 1 byte "present" flag... always 1 for 0x04, I think
		- 2 byte big endian size
		- string, no null terminator
	Code? 0x81 always seems to follow
		Consistent default folder IDs:
			- 81 b9 fc f8 f6 c2 e3 a4 d5 08 01 05 00 (no icon)
			- 81 b9 fc f8 f6 c2 e3 a4 d5 08 01 05 00 (no icon)
			- 81 b9 fc f8 f6 c2 e3 a4 d5 08 00 05 01 (icon url)
			- 81 b9 fc f8 f6 c2 e3 a4 d5 08 00 05 00 (no icon)
			- 81 b9 fc f8 f6 c2 e3 a4 d5 08 00 05 00 (no icon)
			- 81 b9 fc f8 f6 c2 e3 a4 d5 08 00 05 00 (no icon)
			- 81 b9 fc f8 f6 c2 e3 a4 d5 08 00 05 01 (icon url)
		- so:
		- 4 byte ID
		- another 4 byte ID
		- 1 byte unknown
		- 1 byte flag (seen 1 or 0)
	Code: 0x05   (on older devices, this is code 01 as a terminator?)
		- 1 byte "present" flag
			- if 0, then size could be 0x00a5 which adds
			  5 unknown bytes
			- if 1, then size is length of string
		- 2 byte big endian size
		- string here (may be no bytes)
	- 3 byte flags for display mode, javascript mode, and browser id
	  at the end of the section

Needs testing with more device data.